Active suspension systems are used on utility vehicles, such as tractors, harvesting machines, combine harvesters, forage harvesters, self-propelled sprayers, as well as industrial utility vehicles, such as construction vehicles, bulldozers, graders, backhoe excavators, loader vehicles, tipper trucks, cranes and telescopic loaders. Active suspension systems are suspension and damping systems, by means of which movements between a first part and a second part of the vehicle are cushioned and/or dampened. Such systems are known from the prior art, in particular with a seat suspension system of the applicant, which is disclosed in EP 1 186 467 B1. Such active suspension systems are also used in chassis of vehicles—generally large executive cars. A known axle suspension system is described in EP 0 913 280 A1. Such systems exclusively serve to cushion the driver relative to vibrations of the vehicle and/or of the first part and/or to counteract said movements. As a result, comfort is increased during the operation of the vehicle. Such cushioning, however, may lead to a false evaluation of critical driving conditions, as identifiable, tactile feedback between the vehicle and the operator due to the active suspension system no longer being present or the effect of said active suspension system being considerably reduced.
During the operation of a utility vehicle, assistance is provided to the operator visually, or optionally acoustically, by warning display elements. In this connection, warning lights are primarily provided which indicate a critical state of the utility vehicle, for example that of the excessive temperature of the engine oil or the coolant above an upper threshold value. The detection by an operator of such warning signs may be interfered with by external influences, such as light, noise and/or field of vision.